Yesterday’s deal is the first occasion since 1910 that a party from Ireland has, on its own, held the balance of power in the British parliament, able to decide whether a government survives, or falls.

In 1910, the Liberals under Herbert Asquith and John Redmond’s Irish Party combined to keep the Conservative and Unionist Party out of power – a decision that has had consequences for both Britain and Ireland that live until this day.

The 1910 general elections provoked one of the most serious constitutional crisis ever faced in the United Kingdom, following the Liberals’ thumping majority in 1906.

In 1909, the then chancellor of the exchequer, David Lloyd George, introduced the “people’s budget” – a budget which sought to redistribute wealth from the rich to the poor in Britain. It proposed a wealth tax and estate duties which were aimed squarely at the landed classes who occupied the benches of the Conservative-backed House of Lords.

The House of Lords, by tradition, did not veto budgets, but did with this one as Lloyd George expected. The Liberals had anticipated this confrontation. For Lloyd George the future of Britain as a democratic state was at stake.

Could 500 men “chosen accidentally from among the unemployed” , he thundered, frustrate the “deliberate judgment of millions of people” who worked daily in poor conditions to create the country’s wealth.

Swamp Lords

Asquith threatened to swamp the Lords with hundreds of life peers if its occupants did not back down. A year later, he called an election – one he believed he would win easily. Much to his incredulity, Asquith lost his majority and was forced to depend upon Redmond, though the Irishman demanded that the Lords veto be dealt with once and for all as his price.

The Irish Party had reasons to curb the power of the House of Lords, since the chamber had previously vetoed the Home Rule Act of 1893 despite Liberal support. If the veto was not dealt with, Home Rule would never make it on to the statute books in the UK. So the Liberals and Irish Party combined in 1911 to curb the upper chamber’s powers.

Under the change, the Lords could veto a bill twice. If the Commons approved it a third time, it would have to pass. This was to have momentous consequences in 1912 when the Home Rule Act was introduced in the House of Commons.

It was eventually passed at the third attempt in May 1914 and given royal assent (put on the statute books) in September 1914. However, by that stage war had intervened.

Today, the question is what is the price that will be demanded by the Democratic Unionist Party, and what shadows in Irish history will be left by Theresa May’s failed rush to the voters.